1. Field
The present application relates generally to wireless communications, and more specifically to methods and systems for retrieving and using stored context information when a user equipment (UE) transitions between different wireless systems.
2. Background
Wireless communication systems are widely deployed to provide various types of communication content such as voice, data, and so on. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing the available system resources (e.g., bandwidth and transmit power). Examples of such multiple-access systems may include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, Long Term Evolution (LTE) systems, and orthogonal frequency division multiple access (OFDMA) systems.
Generally, a wireless multiple-access communication system can simultaneously support communication for multiple wireless terminals. Each terminal communicates with one or more base stations via transmissions on the forward and reverse links. The forward link (or downlink) refers to the communication link from the base stations to the terminals, and the reverse link (or uplink) refers to the communication link from the terminals to the base stations. This communication link may be established via a single-in-single-out, multiple-in-signal-out or a multiple-in-multiple-out (MIMO) system.
3rd Generation Partnership Project (3GPP) LTE complements the success of High Speed Packet Access (HSPA) with higher peak data rates, lower latency and an enhanced broadband experience in high-demand areas. This is accomplished with the use of wider-spectrum bandwidths, OFDMA and Single-Carrier FDMA (SC-FDMA) air interfaces, and advanced antenna techniques. These techniques enable high spectral efficiency and an excellent user experience for a wide range of converged IP services. For example, Universal Mobile Telecommunication System (UMTS) operators are rapidly adopting and offering IP services such as rich multimedia (e.g., video-on-demand, music download, video sharing), VoIP, PTT and broadband access to laptops and PDAs.
With the deployment of a multitude of wireless technologies worldwide and support for these technologies in mobile multimode devices or user equipment (UE), there is a growing need for uninterrupted connections between UEs and Radio Network Controllers (RNCs) of different Radio Access Networks (RANs). In a heterogeneous wireless access environment that includes, for example, UMTS Terrestrial Radio Access Network (UTRAN) and LTE technologies, it is imperative that LTE-capable systems and UEs be equipped to handle transitions between the different RANs in a seamless manner. Accordingly, there is a need for techniques that allow for the efficient retrieval of utilization of context information from the source and/or target RANs.